School desk of adjustable height



y 1966 P. G. STALNACKE 3,259,081

SCHOOL DESK OF ADJUSTABLE HEIGHT Filed May 9, 1965 2 Sheets-Sheet l FIG, 1

INVENTOR PAUL GUNNAR STDiLNACKE ATTORNEYS July 5, 1966 P. e. STALNACKE 3,259,081

SCHOOL DESK OF ADJUSTABLE HEIGHT Filed May 9, 1963 2 Sheets-Sheet 2 gNVENTOR PAUL GUNNA R STALNACKE ATTORNEYS United States Patent 3,259,081 SCHOGL DESK OF ADJUSTABLE HEIGHT Paul Gunnar Stilnacke, Farsta, Sweden, assignor to Aktiebolaget Skrivrit, Sollentuna, Sweden, a corporation of Sweden Filed May 9, 1963, Ser. No. 279,285

Claims priority, application Sweden, May 10, 1962,

5,249/ 62 4 Claims. (Cl. 108-147) The present invention relates to the kind of school desks of adjustable height which have a pair of legs, each one of which comprises two sections which are mutually displaceable in the axial direction thereof with the aid of a screw spindle provided in each leg, the upper ends of the screw spindles carrying each a bevel pinion in engagement with a bevel pinion on a driving shaft. However, the suggested constructions for journalling the driving shaft and the bevel pinions thereof have the drawback of being either highly complicated or of such simplicity as to be detrimental to the strength and operation thereof.

The invention has for an object to avoid this drawback by providing a suitably journalled and simple construction of the transmission mechanism between the screw spindles of the legs of the desk. According to the invention, the bevel pinions engaging the bevel pinions of the screw spindles are journalled by means of their hubs or prolonged portions thereof in the bottom of slots provided in vertical supporting plates which are fastened to the upper ends of the upper sections of the legs, the pinions being displaceably mounted on the driving shaft but in non-turnable engagement therewith and being subject to compression from the journal plates and shoulder portions provided on the driving shaft so as to ensure the engagement of the said pinions with the pinions of the screw spindles.

The invention is illustrated on the attached drawing in an embodiment shown by way of example. FIG. 1 is a perspective view of an adjustable elevation school desk according to the invention. FIG. 2 is a vertical crosssection on an enlarged scale through the upper part of the desk. FIG. 3 is a section taken on the line III-III of FIG. 2. FIG. 4 shows a detail viewed according to IV-IV of FIG. 3. FIG. 5 is a modification.

The school desk is provided with a pair of parallel inclined legs, each of which consists of a tubular under portion 1 and a tubular upper portion 2 guided thereon. The two under portions 1 are rigidly attached together by a brace 3 and the two upper portions 2 are rigidly attached by a brace 4. Attached to the upper portions 2 is a rectangular wooden frame 5 having a frame of angular iron 5a embedded therein and brackets 6 supported on the upper leg portions 2. A desk box 7 is suspended in the angle iron frame 5a. Attached to the top of the frame 5 is a desk plate 8 and a desk lid 9 is attached to the plate 8 by means of hinges and rests on top of the frame.

As is more clearly apparent from FIGS. 2, 3 and 4, a screw spindle 10 is journalled in each upper leg portion 2 and engages in a known manner by means of threads the under leg portion 1. Each screw spindle 10 carries at the upper end thereof a bevel pinion 11. Welded to the upper end of each upper leg portion 2 is a 3,25%,81 Patented July 5, 1966 "ice vertical journalling plate 12, which is also welded to the angular iron frame 5a. The journalling plate 12 is provided with a slot 13. A first bevel pinion 14 is positioned with its hub supported at the bottom of the slot 13 of one journalling plate 12 and a hub extension 15 of a second bevel pinion 14 is supported on the bottom of the slot 13 of the second journalling plate 12. The pinions 14 have smooth but cornered centre holes 16 and a driving shaft 17 is provided with end portions of similar shape inserted in the corresponding pinions 14 or the hub extension 15, respectively. The driving shaft 17 terminates at one end under the desk plate 8 and is connected thereat with a disconnectable crank 18. The members 14, 15 and 17 are mounted by having the pinions 14 loosely mounted on the driving shaft 17 in contact with angular shoulders 19 thereon and the hub extension 15 is similarly mounted on the shaft 17 and engages the adjacent pinion 14. The members 14, 15 and 17 are mounted by being placed in the slots 13 while they are open, as indicated by dash-dot lines in FIG. 4. The hub of the one pinion 14 and the hub extension 15 of the other pinion 14 engage the slots, which are then closed by bending together the portions (shown in dash-dot lines) of the journalling plates on each side of the outer portions of the slots 13. The bending is facilitated by notches 20 provided in the journalling plates 12. The desk plate 8 mounted over the transmission members referred to is entirely disconnected from these members and is provided with a recess 21 corresponding to the position of the bevel pinions 14 on the driving shaft 17.

It will be immediately clear from the above that the construction according to the invention has the advantage of comprising simple members easily mounted and suitably jou-rnalled. The constructional details are subject to modification, particularly with regard to the closing of the slot 13 in the journalling plates 12. This may also be achieved by means of a pin attached crosswise over the slot or by adapting the under side of the desk plate 8 to lie immediately on top of the driving shaft 17, or by providing at the under side stops which may be adjustable vertically and are placed on top of the driving shaft 17. The hub extension 15 may be integral with its pinion or may be absent, in which case the right-hand pinion 14 of FIG. 3 is journalled directly in the journalling plate 12 in the same way as the left-hand pinion 14, one screw spindle 10 having a left-hand thread and the other a right-hand thread to provide the same height adjustment even when the screw spindles are turned in opposite directions.

It may be preferable to let the two spindles have the same kind of thread. In that case, each bevel pinion 14 is placed, for example, to the right of the corresponding bevel pinion 11, FIG. 5, and a sleeve fitting 15 on the driving shaft is journalled in the left-hand journalling plate 12, and in contact with a shoulder 19 on the shaft 17.

What is claimed is:

1. In a school desk of adjustable height having a substantially horizontal frame and a pair of legs each of which comprises a pair of sections which are mutually displaceable in the axial direction thereof through the action of a screw spindle mounted in each leg, adjustment apparatus comprising: first bevel pinions fixed to the upper ends of said screw spindles for imparting rotation thereto; second bevel pinions in meshing engagement with said first bevel pinions for rotation therewith; a longitudinal drive shaft supporting said second bevel pinions for rotation therewith; substantially vertically disposed journal plates fastened to the upper ends of the upper leg sections and to the frame and having upwardly opening journal slots formed therein; bracing means extending between and connecting said upper leg sections and other points of the frame, means mounted on said drive shaft for rotation therewith and journalled in said upwardly opening slots to support said drive shaft, said last mentioned means being restrained against axial movement in one direction by said journal plates; shoulders formed on said drive shaft for preventing axial movement of said last mentioned means in the other direction; and means for vertically retaining the journalled means in said slots by closing the upper ends of said slots.

2. Apparatus as set forth in claim 1 wherein said means journalled in said slots comprise hub members formed on said second bevel pinions.

3. Apparatus as set forth in claim 1 wherein said means journalled in said slots comprise in part at least one hub extension member extending between one of said slots and one of said second bevel gears.

4. Apparatus as set forth in claim 1 wherein said means for closing the upper ends of said slots comprise portions of said journal plates on each side of each slot, said portions being bent over to close said slots after insertion of said drive shaft and said means journalled in said slots.

References Cited by the Examiner UNITED STATES PATENTS 635,584 10/ 1899 Peregrine 297165 911,843 2/1909 Sample 108147 X 953,719 4/1910 Skripec 108147 X 981,113 1/1911 Richards 108147 2,342,631 2/ 1944 Hillenbrand 108-147 2,368,748 2/ 1945 Doty 108147 2,531,925 11/1950 Taylor et a1. 108147 3,118,705 1/1964 Stalnacke 108-147 X FOREIGN PATENTS 390,214 4/ 1933 Great Britain. 623,981 5/ 1949 Great Britain.

FRANK B. SHERRY, Primary Examiner.

I. T. MCCALL, Assistant Examin r. 

1. IN A SCHOOL DESK OF ADJUSTABLE HEIGHT HAVING A SUBSTANTIALLY HORIZONTAL FRAME AND A PAIR OF LEGS EACH OF WHICH COMPRISES A PAIR OF SECTIONS WHICH ARE MUTUALLY DISPLACEABLE IN THE AXIAL DIRECTION THEREOF THROUGH THE ACTION OF A SCREW SPINDLE MOUNTED IN EACH LEG, ADJUSTMENT APPARATUS COMPRISING: FIRST BEEVEL PINIONS FIXED TO THE UPPER ENDS OF SAID SCREW SPINDLES FOR IMPARTING ROTATION THERETO; SECOND BEVEL PINIONS IN MESHING ENGAGEMENT WITH SAID FIRST BEVEL PINIONS FOR ROTATION THEREWITH; A LONGITUDINAL DRIVE SHAFT SUPPORTING SAID SECOND BEVEL PINIONS FOR ROTATION THEREWITH; SUBSTANTIALLY VERTICALLY DISPOSED JOURNAL PLATES FASTENED TO THE UPPER ENDS OF THE UPPER LEG SECTIONS AND TO THE FRAME AND HAVING UPWARDLY OPENING JOURNAL SLOTS FORMED THEREIN; BRACING MEANS EXTENDING BETWEEN AND CONNECTING SAID UPPER LEGS SECTIONS AND OTHER POINTS OF THE FRAME, MEANS MOUNTED ON SAID DRIVE SHAFT FOR ROTATION THEREWITH AND JOURNALLED IN SAID UPWARDLY OPENING SLOTS TO SUPPORT SAID DRIVE SHAFT, SAID LAST MENTIONED MEANS BEING RESTRAINED AGAINST AXIAL MOVEMENT IN ONE DIRECTION BY SAID JOURNAL PLATES; SHOULDERS FORMED ON SAID DRIVE SHAFT FOR PREVENTING AXIAL MOVEMENT OF SAID LAST MENTIONED MEANS IN THE OTHER DIRECTION; AND MEANS FOR VERTICALLY RETAINING THE JOURNALLED MEANS IN SAID SLOTS BY CLOSING THE UPPER ENDS OF SAID SLOTS. 